Breadcrumb

[1ec5]

OSM should somehow show you the country, region, and city you’re currently zoomed in on. It’d be especially useful when you follow a link and have no idea what part of the map it’s pointing to.

Bing and Multimap provide this context as a dynamic “breadcrumb” at the top of the map. Nominatim is also capable of providing data for a breadcrumb, but the comments in #85 indicate that querying every time you pan or zoom would put too much strain on the geocoder. We should consider a less expensive way to provide context, such as:

1. Make the breadcrumb perhaps less specific than it could be, and only update it after panning a few screens over.
2. Display a specific breadcrumb, but as soon as you pan or zoom, change the wording to “X km from Y, Z” and show a Refresh button.
3. When clicking or mousing over the “Query features” button, briefly show the current breadcrumb. The “Query features” button is currently disabled at z13 and below, so this would give the button something to do when you’ve zoomed too far out to perform an overpass query. We could call the button “What am I looking at?”
4. Include a breadcrumb in the Legend or Share panels. (The Legend panel could have entries for the different administrative boundary patterns, each one labeled with the administrative boundary you’re currently in.)

(Edit: Struck out the latter two suggestions, since that’s no better than the “where am I?” feature we still have.)

The lack of a breadcrumb is sometimes cited on the talk-us mailing list as one reason to insist that refs on state highways indicate the state unambiguously (e.g., “FL 123” in Florida), even where local usage differs (like “SR 123” in some U.S. states). But that tagging rule wouldn’t really solve the problem it’s supposed to. For example, if you’re looking at a city’s central business district or deep within a national park, there may be no state highway within view to tell you which state you’re in. It also isn’t universally agreed that the ref of a highway way should be responsible for providing this information – I can’t tell which county of Ireland I’m in just by looking at highway shields.

[pnorman]

👎 to sticking a location breadcrumb on the query features button - it doesn't seem like a place a user would look for it, and the tooltip should explain what the button is, not provide content.

You've not discussed where "Where am I?" fits into this, given it provides the functionality you are after in a different way. What would happen to Where am I?

[1ec5]

@pnorman Whoops, forgot to update the title as I continued thinking about it. And I wasn’t suggesting bringing back the “where am I?” feature in the same form; I’m more interested in getting something as close to a dynamic breadcrumb as possible.

[1ec5]

@pnorman Oh, heh, wow. I was looking at #85, where it was suggested that “where am I?” be removed, and it didn’t even occur to me that it’s still there. So I guess this is a request for something more immediate and dynamic, like a breadcrumb.

[lonvia]

Reverse geocoding is not that expensive, Nominatim can handle quite a number of requests, especially if we get the second server up and if reverse geocoding is changed to make use of the new postgis 2 functions for finding the closest object.

Gut feeling tells me that it should be possible to have breadcrumbs if you go for an implementation where the breadcrumb is updated not on every move but only a second or so after zooming and panning stops. Naturally, some solid numbers on the load produced would be needed for a definitive answer.

[Zverik]

So it is theoretically possible to add a constantly updated string with reverse geocoded position in a corner of the slippy map, removing "where am I" button?

[tomhughes]

Well of course it's theoretically possible - almost anything is theoretically possible.

[Zverik]

Okay, I meant "practically", like, nominatim server would not be overloaded.

[jase88]

"Where am I" feature isn't very intuitive. Sidebar with 3 results to a simple question (internal coordinates?). I would remove this completely when adding location breadcrumb.

So what is needed to test if nominatim servers are capeable of a "reverse geocoding"-query to every map move? In case this slows osm.org we need better hardware for nominatim server or improvements to the nominatim backend needs to be done ;) Imho frontend issues like this shouldn't deal with backend problematics in first place, but with the idea in general.